Loss on Ignition ; Insoluble Residue

[BigH]

Just wanting to get some thoughts on the ASTM specifications for the two above properties - ASTM C150. It seems that the IR of 0.75% as given in ASTM is quite a bit on the low side - BS standards and Canadian standars permit up to 3% - Indonesian standards 5%. LOI is 5%, too, in Indonesia. Canada and BS are at 3% I think. It looks like we may have a hard time meeting ASTM for these two on our job. We are using relatively low strength mixes - RCC at 12 MPa at 1 year and normal concrete being maxed out at 30 MPa at 90 days. Any thoughts?

 

[Ron]

BigH...LOI has a potentially greater impact on low strength mixes. One problem (assuming all LOI comes from organic material) is the absorption of calcium, thus affecting cement hydration.

In any case, it's good to keep the LOI as low as possible. When you get in the 5% range, that's like a slightly organic soil...not an issue for soil, can be an issue for soil-cement, flowable fill, and low-strength concrete.